1.Population Ecology: (5-3) World Population Clock Fun Website.. 1. Visit the website to watch the world human population clock track those factors that cause a population to change to change in size: births, deaths, immigration and emmigration. 2. Scroll down site to see the list of ALL countries ranked from most populated to least populated. 3. Scroll down to view the human population exponential growth graph. 4. Scroll down to view predictions for human population by 2100.